Engine in most of the oil cooler line failing cases are finished. You might do a compression check to see what is left.

Even with fair to good compression the bearings may be damaged. There is no absolute way to guess his engine. You must assume it is toast unless you prove otherwise.

Again failure of the oil cooling lines dumps all the oil in less than a minute. I personally have never noticed anyones engine surviving this senario before.

The odds are basically against you. You may have a slight chance but percentagewise it is not too high. Just my opinions by the way and if the vendor described the full incident it might enlighten you a little.